I set up something with raspberry Pis using vlc to send and receive rtsp. VLC is a simple solution that can stream a pre-processed and compressed video stream from point A to B using RTSP.
One problem using RTSP is that it’s insecure. It’s not encrypted and if somebody manages to intercept your password, well, most people use the same or a variant of a password in most places. Even if wasn’t useful, I could freely spy on your video feed, even modifying the stream. If these are your security cameras, suddenly they are working against you. If you are watching birds, it’s probably not so important.
RTDP is also a UDP based protocol meaning there is no error correction. This could be important if you are relying on wifi at long-ish ranges. Many dropped packets means holes in the video you can’t fix. This means you need a tcp based protocol like http.
There are plenty of http, flash based solutions out there. I would avoid them given the technology is deprecated and support is poor for mobile devices. The last I looked into this the technology was shifting towards html5 video, however there are plenty of other streaming video protocols.
You could just have a samba/nfs/SFTP share on a server somewhere and the cameras perioidically connect to coy their new video files over (or write directly). That’s may be a good solution if your cameras are battery powered. You can even power down wifi this way. Really it all depends on what your needs are. You may be able to get away with using RTSP or you may need something more.